This study is being performed to help patients and their health care team work together to make decisions about managing their asthma. A new class of medicines for asthma called asthma biologics, which target very specific immunological pathways responsible for asthma, were developed. The first such medicine, omalizumab, first became available in 2003 and 2 additional medicines, mepolizumab and reslizumab, became available in 2015 and 2016, respectively. These medicines are currently intended for those who have moderate or severe asthma and who haven't responded to other asthma medicines like inhaled corticosteroids. Patients receiving asthma biologics usually have the highest burden of asthma disease. Asthma biologic medicines are very expensive and may not work for everyone. Sometimes, patients and their doctors need to make decisions about stopping asthma biologics. Right now, we do not have very good information about what happens to patients after they stop these medicines. It is important to get a better idea of the risk of stopping asthma biologic medicines and to be able predict who may be able to stop them with lower risk of future asthma attacks. The over-arching, long-term objective of the research is to improve the lives of people who have asthma. In this study, we are using a very large data set that allows us to study over 4,000 patients who have started taking the first asthma biologic, omalizumab, and then comparing what happens in patients who continue taking omalizumab with patients who stop taking omalizumab. We will then extend the same comparison to the other asthma biologic medicines, mepolizumab and reslizumab. The specific aims of the proposal are listed below. Specific Aim #1: Determine the outcomes following discontinuation of inhaled corticosteroids, mepolizumab, omalizumab, and reslizumab for asthma in real-world practice settings. Specific Aim #2: Develop and validate predictive models for safe discontinuation of asthma biologic medications. The methods we will use involve the analysis of existing data. We believe these methods will lead to a more rapid assessment than the current process for making these determinations, which include disease registries and phase IV clinical trials. When this study is complete, patients and their healthcare team will have access to more confident risk estimates for asthma biologic discontinuation, thus leading to better decisions about asthma biologic treatments and improved health for people who suffer the greatest disease burden.